1. Technical Field
The invention relates to a method for treating mixed waste by pyrolysis, said method comprising carbonizing organic mass by heating in a pyrolysis reactor in an oxygen-free environment to carbon, distilling pyrolysis gases for oil and using the gases for energy production, screening solid matter produced in pyrolysis for separating inorganic coarse particles from a carbon fraction, and milling and classifying the carbon fraction.
The invention relates also to an apparatus for treating mixed waste by pyrolysis, said apparatus comprising a feed conveyor for mixed waste, a dewaterer, a reusable magazine carriage, a pyrolysis reactor, which is supplied with mixed waste by the conveyor and in which organic mass is heatable in an oxygen-free environment to carbon, an oil distillation column for distilling pyrolysis gases for oil while cleaning the gas, a sieve for screening solid matter resulting from the pyrolysis reactor for a fraction containing primarily carbon, and milling equipment for milling the carbon fraction, as well as a classifier and air cleaner for separating and recovering pure carbon.
2. Discussion of the Background
Patent publication U.S. Pat. No. 6,244,198 discloses a method and apparatus for the pyrolytic treatment of organic material. This prior known apparatus can be used also in the present invention as a pyrolysis reactor. Waste disposal methods and equipment, based on pyrolysis, are known in large numbers, notable examples including Patent publications U.S. Pat. No. 5,725,738 and EP-0905213. However, these prior art methods and equipment do not provide a sufficient solution for the after-treatment and grading of carbon produced in pyrolysis. However, this would be of paramount importance in terms of using recovered carbon and recycling the same for reutilization. Another unsolved problem with prior art pyrolysis reactors is the fact that the dewatering of waste to be fed into a pyrolysis reactor and the purification of water recovered therefrom have not been worked out with sufficient efficiency. The method and apparatus known from International Patent application WO 01/04235 are provided with preheating and dewatering of wastes, but there is no proposal for purification of water recovered therefrom.